When conduction controlled rectifiers connected in a power frequency converter consisting of bridge-configured rectifier-inverter circuits are used to provide pulse code signals to power lines for control of peak demand loads, it is necessary to switch the conduction controlled rectifiers in the inverter on and off to generate the desired pulse code. During this switching, if one pair of the three pairs of conduction controlled rectifiers of the inverter is on at the same time, there will be a short of the DC power supply through the inverter silicon control rectifiers (SCRs). This condition is known as "shoot-through".
This invention relates to a detector for sensing the shoot-through condition, and means for providing a path of current flow which will protect the inverter SCRs during the shoot-through condition.